narrow DeepSeek Flash tools for forced phases

src/clean_agent_preview.py

@@ -186,6 +186,18 @@ def provider_compatible_tool_choice_request(request, model):
     """Keep tools but avoid forced choice unsupported by thinking providers."""
     if canonical(model) == 'deepseek-flash' and 'tool_choice' in request:
         compatible = dict(request)
+        choice = compatible.get('tool_choice')
+        selected_name = (
+            (choice.get('function') or {}).get('name')
+            if isinstance(choice, dict) else None
+        )
+        if selected_name:
+            selected = [
+                schema for schema in compatible.get('tools') or []
+                if (schema.get('function') or {}).get('name') == selected_name
+            ]
+            if selected:
+                compatible['tools'] = selected
         compatible.pop('tool_choice', None)
         return compatible
     return request

tests/test_clean_agent_preview.py

@@ -100,12 +100,15 @@ def test_provider_wire_messages_drops_empty_assistant_placeholder():
 def test_deepseek_flash_keeps_tools_but_drops_unsupported_forced_choice():
     request = {
         'model': 'deepseek-flash',
-        'tools': [{'type': 'function', 'function': {'name': 'inspect_media'}}],
+        'tools': [
+            {'type': 'function', 'function': {'name': 'inspect_media'}},
+            {'type': 'function', 'function': {'name': 'python'}},
+        ],
         'tool_choice': {'type': 'function', 'function': {'name': 'inspect_media'}},
     }
 
     compatible = provider_compatible_tool_choice_request(request, 'deepseek-flash')
-    assert compatible['tools'] == request['tools']
+    assert [tool['function']['name'] for tool in compatible['tools']] == ['inspect_media']
     assert 'tool_choice' not in compatible
     assert request['tool_choice']['function']['name'] == 'inspect_media'
     assert provider_compatible_tool_choice_request(request, 'qwen3.5-9b') is request